Liquid inspection system and apparatus



Aug. 23, 1966 N. F. ROBINSON 3,267,723

LIQUID INSPECTION SYSTEM AND APPARATUS Filed Dec. 18, 1963 2Sheets-Sheet 1 04 /0 Z INVENTOR. Mam fiw/wm A 966 N. F. ROBINSON LIQUIDINSPECTION SYSTEM AND APPARATUS 2 Sheets-Sheet 2 Filed Dec. 18, 1965 711 g. wwA ffgii on/ United States Patent ()ffice 3,267,723 PatentedAugust 23, 1966 3 267,723 LIQUID INSPECTION SYSTEM AND APPARATUS NormanF. Robinson, Manhattan Beach, Calif, assignor to Douglas AircraftCompany, Inc, Santa Monica, Calif.

Filed Dec. 18, 1963, Ser. No. 331,474 Claims. (Cl. 7361) The presentinvention relates generally to liquid inspection systems and apparatusfor determining the presence of contaminants in liquids and moreparticularly to a modification of the systems and apparatuses shown incopending applications Serial No. 134,687 filed September 12, 1961, nowabandoned, and Serial No. 197,198 filed May 22, 1962, these priorapplications being assigned to the common assignee hereof.

The successful operation of many systems used to conduct liquids dependsupon maintaining the system in a contamination-free condition. Forexample, hydraulic fluids utilized to operate valves, hydraulicactuators, positioners and the like, on aircraft, missiles and the like,must be maintained in a contamination-free condition for satisfactoryoperation of the devices.

Contaminants that are usually found in hydraulic fluids and the likegenerally take the form of organic and inorganic particles which fiindtheir way into the hydraulic fluid prior to placement in the system inwhich it is used, or are generated within the system by wear of themoving parts. Although the hydraulic fluids used in the describedsystems are carefully cleaned and filtered prior to injection into thesystem, contaminants in the order of 0.1 to 10 microns, or larger, mayfind their way into the system or be generated within it. Thesecontaminants, while affecting operation of equipment associated withhydraulic systems, are extremely difficult to detect in the absence ofrelatively elaborate laboratory facilities. The problem is furthercomplicated by the fact that it is desirable to detect the contaminantin certain hydraulic fluid systems while the systems are in operationand, in some cases, while the systems are pressurized. Under theseconditions, the contaminants are generally maintained in suspension.

Prior to the liquid inspection systems and apparatuses of saidco-pen-ding applications, hydraulic fluid systems were examined orchecked for contaminants by removing some fluid from the system forexamination in a remote laboratory.

The systems and apparatuses of said co-pending applications, on theother hand, are connectible directly into the hydraulic system to beinspected so that a sample need not be taken from the system forsubsequent examination in a laboratory.

The liquid inspection system and apparatus of the present invention isof the type which may be incorporated directly into the hydraulic systemto be examined, but is modified in certain respects from those shown insaid co-pending applications.

Accordingly, it is one important object of the present invention toprovide a liquid inspection system and apparatus which is a modificationof the systems and apparatuses shown in co-pending applications SerialNo. 137,687 filed September 12, 1961 (now abandoned) and Serial No.197,198 filed May 22, 1962.

It is another important object of the present invention to provide asystem and apparatus for determining the presence of contaminants in aliquid not subject to the disadvantages of prior art systems andapparatuses.

Another object of the present invention is to provide a contaminantdetermining system and apparatus used in connection with liquid systems,while such systems are in operation and at the site of operation of thesystem.

Another object of the present invention is to provide a new and usefulsystem and apparatus of the type described for determining the presenceof contaminants in a liquid.

A still further object of the present invention is to provide a systemand apparatus of the type described for determining contaminant contentin liquids wherein a sample of the liquid may be obtained from anoperating system and examined without introducing additionalcontaminants to the liquid under examination.

According to the present invention, an apparatus of the invention isattached to the hydraulic pressure and return lines of the system to beexamined thereby trapping a sample of the hydraulic fluid within theapparatus. The hydraulic-fluid sample is then flushed with a filteredsolvent and filtered through a field monitor which contains a filterpatch. Dry nitrogen or the like is then employed to dry the patch. Thefield monitor is then removed from the apparatus and a comparison checkmade with an acceptable standard filter patch using a magnifier. Thefield monitor includes a plastic housing assembly having an inlet portwhich may be quickly snapped into place on a drain poppet at the bottomof the apparatus.

The features of the present invention which are believed to be novel areet forth with particularity in the appended claims. The presentinvention, both as to its organization and manner of operation, togetherwith further objects and advantages thereof, may best be understood byreference to the following description, taken in connection with theaccompanying drawings, in which:

FIGURE 1 is a perspective view of the apparatus of the present inventionmounted in its carrying case;

FIG. 2 is a perspective view of a cover for the carrying case of FIG. 1showing certain components of the apparatus in position therein;

I FIG. 3 is an elevational view of the portion of the apparatus of thepresent invention which is housed in the bottom of the carrying case ofFIG. 1;

FIG. 4 is a cross-sectional view showing somewhat schematically theoperating circuits of the apparatus of the present invention withcertain part thereof shown in a first operating condition; and

FIG. 5 is an enlarged cross-sectional view of certain parts of FIG. 4 ina second operating condition.

Referring again to the drawings, the apparatus of the present inventioncomprises a test kit, generally designated 10, and includes a carryingcase 12 in which a wall partition member 14 is swingably mounted onhinges 16. The carrying case 12 has an open top 17, an encompassingsidewall 18 and a closed bottom wall 20. A cover member 22 may besnapped into position on the carrying case 12 by snaps 24 to close theopen top 17.

When the cover 22 is removed from case 12 as shown in FIG. 2, ahydraulic fluid sampler 26, a sight. glass 28, a solvent-tank fillerneck 30, a selector switch 32, a nitrogen tank pressure gauge 34 and anitrogen inlet fitting 36 are exposed.

The hydraulic fluid sampler 26 is attached to a front face 38 of thepartition 14 by suitable bolts, such as the one shown at 40. Thehydraulic fluid sampler 26 includes a lower housing member 42 in which ahydraulic fluid inlet port 44 is mounted and an upper housing member 46in which a hydraulic fluid outlet port 48 is mounted. The housingmembers 42 and 46 are connected together as by bolts 50. The upperhousing member 46 also includes a solvent inlet port 52.

A solvent tank 54 (FIG. 3) and a pressurized nitrogen tank 56 areattached to a rear face 58 of the partition 14 by suitable bolts 60. Thesolvent tank 54 includes the filter neck 30 (FIG. 1) which extendsthrough the partition 14 to the front face 38, as previously described.The

filler neck 30 is normally closed with a cap 62. The solvent tank 54(FIG. 4) also includes an encompassing sidewall 64, a closed bottom wall66 and a closed top wall 68. A nitrogen inlet port 70 is mounted in thetop wall 68 for admitting nitrogen under pressure to the tank 54 and asolvent outlet port 72 is mounted in the top wall 68 in communicationwith a depending stand pipe 74 through which solvent under pressureflows from the tank 54. A conduit or line 76 connects the nitrogen inletport 70 to a port 33b in the selector switch 32 and a conduit or line 78connects the outlet port 72 to a port 33a in the switch 32. A conduit orline 80 connects the switch 32 to the solvent inlet port 52 and aconduit or line 82 connects the switch 32 to a relief valve 84. Aconduit or line 86 connects the relief valve 84 to a nitrogen pressureregulator 88 which, in turn,'is connected to the nitrogen cylinder 56 bya conduit or line 90 through a shutofl valve 92. The valve 92 includesan L-fitting 94 to which the nitrogen inlet 36 is connected by a conduit98.

The sight glass 28 is connected to the solvent tank 54 to indicate thelevel of solvent therein. Flexible conduits 100 and 102 are connected tothe hydraulic fluid inlet port 44 and the outlet port 48, respectively.The flexible conduits 100 and 102 each carry a hose fitting 104 (FIG. 3)which may be employed to connect the hydraulic fluid sampler 26 to ahydraulic system, not shown, to be tested.

Fluid to be tested flows through the flexible conduit 100, and the inletport 44 unseating a poppet valve 106 (FIG. 4). The fluid then flows intoa chamber 108 in the sampler 26. The chamber 108 extends from the lowerhousing member 42 into the upper housing member 46. The lower housingmember 42 includes a partition 109 in which an outlet port 110 ismounted. The port 110 is normally closed by a poppet valve 112 shownseated in FIG. 4 by a leaf spring 114. A partition 115 is mounted in theupper housing member 46 and is provided with an inlet port 116 which isnormally closed by a poppet valve 118 biased to a closed position by aspring 120. An outlet port 122 is also mounted in the upper housingmember 46 and is normally closed by a ball-type check valve 124 which ismaintained in a seated condition by a spring 126. Since the valves 112and 118 are closed as shown in FIG. 4 when the fluid enters the chamber108, it must flow upwardly in the direction of arrow 128 unseating thecheck valve 124 and flowing through the outlet port 48 into the returnconduit 102. This fills the chamber 108 with fluid to be tested afterwhich flow through the inlet conduit 100 is terminated.

The sampler 26 is put into condition to test the fluid in chamber 108 byplacing a filter patch and pad assembly 130 on top of a support disc 132in the open top 133 of upper housing member 46 above partition 115.After the filter patch 130 is in position, a cover member 134 is placedon the top of the upper housing member 46 and sealed thereto with anO-ring 136. The cover member 134 is maintained in position by a yoke andscrew assembly 138 which is swingably mounted on the upper housingmember 46 by suitable bolts, such as the one shown at 139 in FIG. 1.

The sampler 26 is further conditioned to test the fluid in chamber 108by removing a base adapter ring 140 from its threaded engagement withthe open bottom 141 of lower housing member 42 and connecting a fieldmonitor 142 (FIG. to the outlet port 110. The field monitor 142 includesan inlet neck 144 which carries an O-ring 146. The inlet neck 144engages the poppet valve 112 unseating it to permit flow of fluid fromthe chamber 108 through the outlet 110 and into the field monitor 142.The O-ring 146 prevents leakage of fluid past the inlet neck 144.

The field monitor 142 also includes an outlet neck 148 to which aflexible tube 150 may be attached to direct the fluid flowing fromchamber 108 to a waste receptacle, not shown. A test patch and padassembly 152 is supported in the field monitor 142 on a disc 154. Thefilter patches contaminant particles that are desired for collection.

130 and the test patches 152 may be of any suitable material having aporosity commensurate with the size of In testing hydraulic fluid atmissile installations, openings in the order from 0.1 to 10 microns havebeen satisfactory. Particularly, a test patch suitable for such testingis that manufactured by the Millipore Filter Corporation of Bedford,Massachusetts, and sold under the trade name of Millipore filter. Thisparticular test patch is in the order of 0.010 inches to 0.020 inches inthickness, is usually white in color and is made from a fibrous materialhaving a high void to solids ratio. Particularly, the voids may occupy70 to percent the area of the filter while still retaining the 0.1 to 10micron openings. The field monitor consists of the same filter membraneenclosed in a clear plastic capsule, and is also manufactured byMillipore Filter Corporation.

The filter patch is employed to filter solvent from tank 54 and nitrogenfrom tank 56 which enters the open top 133 above the filter 130 throughinlet port 52 and a passageway 156. This is to prevent contaminantspresent in the solvent or nitrogen from appearing on the test patch 152in field monitor 142.

Referring now particularly to FIG. 2, a supply field monitor 142 isstored in the cover 22 in which a pouch and a 5X power viewer 162 arealso mounted. The pouch 160 includes a pocket 165 in which a pair offorceps or the like (not shown) may be stored, a pocket 166 in whichadditional filter patches 130 may be stored and a pocket 168 in whichadditional test patches may be stored.

Operation of the device of the present invention will be readilyunderstood.

The test kit 10 may, for example, be used to monitor periodically forcontamination in the hydraulic fluid used in a hydraulic system teststand (not shown). A hydraulic system test stand is sometimes used fortesting various missile components. The hydraulic fluid becomescontaminated by being pumped through these missile components andreturned to the test stand. A built-in selfcleaning system isincorporated in the hydraulic test stand and a periodical check with thetest kit 10 is used to check the validity of the self-cleaning system.The validity of the self-cleaning system is checked by taking a sampleof hydraulic fluid therefrom and testing it to determine the particlecontamination content in the hydraulic fluid. This sample may beprocured by connecting the flexible conduit 100 to the hydraulicpressure line of the test stand while the flexible conduit 102 isconnected to the return line of the test stand to admit hydraulic fluidunder pressure into chamber 108 of sampler 26 when valves 112 and 118are closed.

The nitrogen gauge 34 is then checked to make sure that it indicatesthat the nitrogen tank 56 is from one-half full to full.

The sample selector 32 is then checked to make sure it is in its -oflposition. The sight gauge 28 on the solvent tank 54 is checked to insurethat it indicates a minimum of 2 inches of fluid in the solvent tank. Ifthe sight glass 28 shows less than 2 inches, the solvent tank 54 must befilled through filler neck 30 with a clean solvent such as Freon TF(113) commercial grade solvent to within /2 inch of the top of the sightglass 28. Flled with solvent and compressed nitrogen, the sampler isindependent of any external power such as electricity or pneumaticpressure or vacuum.

The next step is to verify that hydraulic pressure has been disconnectedfrom the sampler 26. The yoke assembly 138 can then be loosened andswung aside so that the cover member 134 may be removed to expose thefilter patch 130. A new filter 130 is required after about every thirdtest and extra filter patches may be obtained from pocket 166 in the lid22. Forceps, which may be stored in pocket 164, may be used to place anew filter patch 130 in upper body member 46. The base adapter ring 140is then removed and a field monitor 142 is taken from lid .22 andexamined to assure that it has a test patch 152 properly mountedtherein. The field monitor 142 is positioned in the base adapter ring140 which is then tightened into the open bottom 141 of lower housingmember 42 in such a manner that neck 144 engages poppet valve 112 tounseat it. The hose 150 may then be attached to the neck 148 on fieldmonitor 142 and the free-end of hose 150 may be placed in a waste tank,not shown.

The nitrogen valve 92 may then be opened and the sample selector switch32 moved to the position marked solvent on partition 14. With theselector switch 32 in the position marked solvent, the port 33a ofselector 32 places conduit 78 in fluid communication with fluid conduit80 and the port 331) places the conduit 76 in fiuid communication withthe conduit 82. Since the nitrogen valve 92 is open, nitrogen underpressure flows from tank 56 through conduit 90, pressure regulator 88,line 86, relief valve 84, line 82, port 33b, and line 76 into solventtank 54 pressurizing it. Solvent then flows from tank 54 through standpipe 74, outlet port 72, conduit 78, port 33a, conduit 80, inlet port52, passageway 156, and filter patch 130. The pressure of the solventthen unseats poppet valve 118 and flows into chamber 108 forcing thehydraulic fluid therein contained through outlet 110 in the bottom ofsampler 26, the field monitor 142 and the hose 150. Hydraulic fluid isallowed to drain through the hose 150 until the color of the fluiddisappears and clear solvent is observed. The sample selector switch 32is then moved to the nitrogen position on partition 14 to place thenitrogen bottle 56 in fluid communication with the line 80. Nitrogenfrom tank 56 then flows through line 90, valve 92, regulator 88, line86, relief valve 84, line 82, port 331), line 80, inlet port 52,passageway 156, filter 130, check valve 118, chamber 108, outlet port110, test patch 152, and line 150 to waste. The nitrogen is permitted toflow a minimum of one minute and a maximum of two minutes to dry thetest patch 152. The test patch 152 must be thoroughly dried. Moreeconomical usage of nitrogen results when the selector switch 32 isswitched off and on intermittently while residual solvent drains fromthe sampler 26.

The sampler selector switch 32 is then moved to its off position and thefield monitor 142 is removed from the sampler 26 by loosening baseadapter ring 140. The 5 X power viewer 162 is then positioned to view astandard test patch, not shown, and the test patch 152 from the fieldmonitor simultaneously so that the two patches may be compared. If thetest patch 152 indicates contamination above acceptable limits, itbecomes necessary to recirculate the hydraulic fluid through thehydraulic test stand filtering system.

While the particular liquid inspection system and apparatus herein shownand described in detail is fully capable of attaining the objects andproviding the advantages hereinbefore stated, it is to be understoodthat it is merely illustrative of the presently preferred embodiment ofthe invention and that no limitations are intended to the details ofconstruction or design herein shown other than as defined in theappended claims.

I claim:

1. Apparatus for determining the presence of contaminants in a liquidcomprising:

a fluid housing having an open bottom and an open a first liquid inletport mounted in said housing above said open bottom;

a first poppet valve normally closing said first inlet port;

a first partition mounted in said housing intermediate said first inletport and said open bottom;

a first liquid outlet port mounted in said first partition incommunication with said open bottom;

a second poppet valve normally closing said first outlet port;

' a second liquid outlet port mounted in said housing intermediate saidfirst inlet port and said open top;

a check valve mounted in said second outlet port for permitting flow ofliquid from said housing while preventing back flow into said housing;

a second partition mounted in said housing intermediate said open topand said second outlet port;

a second liquid inlet port mounted in said second partition for placingsaid open top in fluid communication with said housing;

a normally closed poppet valve mounted in said second inlet port forpermitting flow of fluid into said housing while preventing flow offluid from said housing;

a first filter patch mounted in said open top above said second inletport;

a third inlet port mounted in said housing in fluid communication withsaid open top above said first filter patch;

a removable cover member for closing said open top above said firstfilter patch; and

a field monitor positionable in said open bottom, said field monitorhousing a second filter patch and including an inlet neck engageablewith said first outlet valve to unseat said valve and permit flow ofliquid from said housing through said first outlet port and said secondfilter patch.

2. The apparatus of clami 1 including a solvent containing tank in fluidcommunication with said third inlet port for directing a solvent throughsaid first filter patch, said second inlet port, said first outlet portand said second filter patch.

3. The apparatus of claim 2 including a nitrogen-containing tank influid communication with said solvent tank to pressurize said solventtank.

4. The apparatus of claim 3 including a selector switch for selectivelyplacing said nitrogen tank in fluid communication with said solvent tankand simultaneously placing said solvent tank in fluid communication withsaid third inlet port, and for placing said nitrogen tank in fluidcommunication with said third inlet port.

5. The apparatus of claim 4 wherein said solvent tank and said nitrogentank are mounted on one side of a wall partition member and said housingis mounted on the otherside of said wall partition member.

6. The apparatus of claim 5 wherein said wall partition member isswingably mounted in a carrying case having an open top and a closedbottom.

7. The apparatus of claim 6 including a lid for closing said open top ofsaid case.

8. Apparatus for determining the presence of contaminants in a liquid,comprising:

a carrying case including an open top and a closed bottom, and having awall partition member swingably mounted in said case;

a fluid housing mounted on one side of said wall partition member andincluding a filter which is pervious to said liquid and impervious tosaid contaminants,

means for mounting said liquid filter to means for conducting a quantityof said liquid through said liquid filter, said contaminants beingretained by said liquid filter, and

means for thereafter conducting a solvent through said liquid filter toremove substantially all residue of said liquid from said liquid filterwhereby said contaminants will be exposed for inspection, said solventconducting means including means for filtering said solvent prior topassage thereof through said liquid filter; and

a solvent containing tank in communication with said solvent conductingmeans, said solvent tank being said housmounted on the other side ofsaid wall partition member.

9. Apparatus for determining the presence of contaminants in a liquid,comprising:

a carrying case including an open top and a closed bottom, and having anormally horizontal wall partition member swingable to a verticalposition mounted in said case;

a fluid housing mounted on the normally top side of said wall partitionmember and including a filter which is pervious to said liquid andimpervious to said contaminant,

means for mounting said liquid filter to said housmeans for conducting aquantity of said liquid through said liquid filter, said contaminantsbeing retained by said liquid filter, and

means for thereafter conducting a solvent and then a' gas through saidliquid filter to remove susbtantially all residue of said liquidfromsaid liquid filter and dry the same whereby said contaminants will beexposed for inspection, said solvent and gas conducting means includingmeans for filtering said solvent and gas prior to passage thereofthrough said liquid filter; and

a solvent containing tank and a gas containing tank in communicationwith said solvent and gas conducting means, said solvent tank and saidgas tank being mounted on the normally bottom side of said wallpartition member.

10. Apparatus for determining the presence of contaminants in a liquid,comprising:

a fluid housing connected to the normally top side of said wallpartition member and including a filter which is pervious to said liquidand impervious to said contaminant,

means for mounting said liquid filter to said housmeans for conducting aquantity of said liquid through said liquid filter, said contaminantsbeing retained by said liquid filter, and

means for thereafter conducting a solvent and then a gas through saidliquid filter to remove substantially all residue of said liquid fromsaid liquid filter and dry the same whereby said contaminants will beexposed for inspection, said solvent and gas conducting means includingmeans for filtering said solvent and gas prior to passage thereofthrough said liquid filter; and

a solvent containing tank and a gas containing tank in communicationwith said solvent and gas conducting means, said solvent tank and saidgas tank being mounted on the normally bottom side of said wallpartition member, and said solvent tank having a filler neck and sightglass connected through said wall partition member to be positioned onthe normally top side of the same and said gas tank having an inletfitting connected through said wall partition member to be positioned onthe normally top side of the same.

References Cited by the Examiner UNITED STATES PATENTS 2,187,514 1/1940Gardner 7361 a carrylng case including an open top and a closed bot-2,599,742 1952 Bomber et 1 7 X tom, and having an inner wall partitionmember 3,049,000 3/1962 Painter et 1 mounted in said case; 35

a lid for closing said open top of said case; DAVID SCHONBERG, PrimaryExaminer.

1. APPARATUS FOR DETERMINING THE PRESENCE OF CONTAMINANTS IN A LIQUIDCOMPRISING: A FLUID HOUSING HAVING AN OPEN BOTTOM AND AN OPEN TOP; AFIRST LIQUID INLET PORT MOUNTED IN SAID HOUSING ABOVE SAID OPEN BOTTOM;A FIRST POPPET VALVE NORMALLY CLOSING SAID FIRST INLET PORT; A FIRSTPARTITION MOUNTED IN SAID HOUSING INTERMEDIATE SAID FIRST INLET PORT ANDSAID OPEN BOTTOM; A FIRST LIQUID OUTLET PORT MOUNTED IN SAID FIRSTPARTITION IN COMMUNICATION WITH SAID OPEN BOTTOM; A SECOND POPPET VALVENORMALLY CLOSING SAID FIRST OUTLET PORT; A SECOND LIQUID OUTLET PORTMOUNTED IN SAID HOUSING INTERMEDIATE SAID FIRST INLET PORT AND SAID OPENTOP; A CHECK VALVE MOUNTED IN SAID SECOND OUTLET PORT FOR PERMITTINGFLOW OF LIQUID FROM SAID HOUSING WHILE PREVENTING BACK FLOW INTO SAIDHOUSING; A SECOND PARTITION MOUNTED IN SAID HOUSING INTERMEDIATE SAIDOPEN TOP AND SAID SECOND OUTLET PORT; A SECOND LIQUID INLET PORT MOUNTEDIN SAID SECOND PARTITION FOR PLACING SAID OPEN TOP IN FLUIDCOMMUNICATION WITH SAID HOUSING; A NORMALLY CLOSED POPPET VALVE MOUNTEDIN SAID SECOND INLET PORT FOR PERMITTING FLOW OF FLUID INTO SAID HOUSINGWHILE PREVENTING FLOW OF FLUID FROM SAID HOUSING; A FIRST FILTER PATCHMOUNTED IN SAID OPEN TOP ABOVE SAID SECOND INLET PORT; A THIRD INLETPORT MOUNTED IN SAID HOUSING IN FLUID COMMUNICATION WITH SAID OPEN TOPABOVE SAID FIRST FILTER PATCH; A REMOVABLE COVER MEMBER FOR CLOSING SAIDOPEN TOP ABOVE SAID FIRST FILTER PATCH; AND A FIELD MONITOR POSITIONABLEIN SAID OPEN BOTTOM, SAID FIELD MONITOR HOUSING A SECOND FILTER PATCHAND INCLUDING AN INLET NECK ENGAGEABLE WITH SAID FIRST OUTLET VALVE TOUNSEAT SAID VALVE AND PERMIT FLOW OF LIQUID FROM SAID HOUSING THROUGHSAID FIRST OUTLET PORT AND SAID SECOND FILTER PATCH.